Change global.is64bit to bool
optimize takes a bool
Implicit int -> bool in isxxx
Implicit int -> bool
Implicit STC -> bool in VarDeclaration::semantic
Don't shadow variable 'ad' in FuncDeclaration::semantic
Implicit int -> bool in functionSemanticX
scondApply should return a bool
Type::isintegral should return a bool
Dsymbol_canThrow and Expression::canThrow should return bool
Type::isunsigned should return bool
Merge pull request #2729 from yebblies/implicitbool

[DDMD] Implicitbool